Poor Sleep Elevates Fall Risk for Older Women

SAN FRANCISCO -- For older women, poor sleep at night may be an independent risk factor for falls, according to researchers here.

Action Points

Explain to interested patients that the study adds some objective evidence to the link between risks of falls and sleep problems.

Note that polysomnography is the gold standard for objective measurement of sleep, but actigraphy allows at-home measurements over the course of days.

SAN FRANCISCO, Sept. 8 -- For older women, poor sleep at night may be an independent risk factor for falls, according to researchers here.

Sleeping five or fewer hours a night significantly increased the odds of having two or more falls in a given year by 52% while sleep fragmentation measures also increased the risk, reported Katie L. Stone, Ph.D., of the California Pacific Medical Center Research Institute, and colleagues in the Sept. 8 issue of the Archives of Internal Medicine.

In their large actinography study, the use of benzodiazepine sleep aides did not explain the association with sleep quality. Daytime catnaps did not affect the risk.

Given that falls are so common in older adults and are a leading cause of mortality, morbidity, and premature nursing home placement, Dr. Stone said it is crucial for physicians to ask patients about sleeping problems and consider treatment options.

This may be particularly important for women who have had a prior fall, which is one of the strongest risk factors for a subsequent fall, she said.

However, she cautioned that there is little evidence to determine whether improving sleep with newer, nonsedating sleep medications or behavioral therapy could reduce fall risk.

Fall risk has been linked to insomnia and other sleep characteristics as well as to benzodiazepine use in prior studies, but these have been limited by self-report or lack of control for other factors.

So the researchers analyzed findings for 2,978 mostly community-dwelling women ages 70 and older (mean 83.5) in the larger Study of Osteoporotic Fractures.

These women wore a wrist actigraph to measure sleep and daytime inactivity for at least three consecutive 24-hour periods. They averaged 6.8 hours of sleep over a 24-hour period and slept 77.3% of the time spent in bed on average.

Over the subsequent year, 18.4% of the women fell at least twice as reported on a triennial questionnaire.

Sleep duration was a significant factor in fall risk even after adjustment for age, race, body mass index, comorbidities, and use of use of benzodiazepines, antidepressants, and antipsychotics.

Women who slept for five or fewer hours were significantly more likely to have at least two falls than those with the "normal" seven to eight hours a night (odds ratio 1.52, 95% confidence interval 1.03 to 2.24).

Extended sleeping -- more than eight hours a night -- tended to increase fall risk but lost significance in the multivariate analysis (OR 1.30, 95% CI 0.94 to 1.81).

Poor quality and fragmented sleep also appeared to be an important determinant of risk of recurrent falls.

Women with poor sleep efficiency of 70% or lower were at 1.36-fold greater risk of falling than those who spent a greater proportion of their time in bed sleeping rather than tossing and turning (OR 1.36, 95% CI 1.07 to 1.74).

However, unlike in a prior analysis of the study, napping didn't affect risk of falls or significantly interact with total sleep time.

After controlling for total sleep time and other variables, benzodiazepines did not significantly increase the risk of falls among the 7.2% of women who reported using them (OR 1.34, 95% CI 0.95 to 1.90).

"These findings suggest that the association between the use of these medications and risk of falls among older adults may be in part explained by poor sleep," the researchers said, "a possibility which has never been explored using objective measures of sleep."

One factor that appeared to explain how sleep impacted fall risk was walking speed, which when added to the multivariate model attenuated the associations.

Walking speed could be a causal factor or a marker for physical frailty, which is linked to both sleep and falls, Dr. Stone's group noted.

They cautioned that the results would not generalize to nursing home patients or other populations such as men and younger adults.

Also, actigraphy, although objective, is not a definitive measure of sleep, they said. Sleep problems seen with this method could reflect sleep-related breathing disorders or other disorders, they added.

Randomized trials are needed to determine whether newer insomnia medications or cognitive behavioral therapy could reduce the risk of falls for older adults, the investigators said. Further study is also needed to determine which specific sleep characteristics are responsible for the associations, they said.

Dr. Stone reported being a consultant for Sepracor and an invited speaker for sanofi-aventis. Co-authors reported conflicts of interest for Arena, Cephalon, Neurocrine Biosciences, sanofi-aventis, Sepracor, and Takeda Pharmaceuticals North America.

This study was supported by Public Health Service grants.

Reviewed by Zalman S. Agus, MD Emeritus Professor University of Pennsylvania School of Medicine

MedPageToday is a trusted and reliable source for clinical and policy coverage that directly affects the lives and practices of health care professionals.

Physicians and other healthcare professionals may also receive Continuing Medical Education (CME) and Continuing Education (CE) credits at no cost for participating in MedPage Today-hosted educational activities.